RF tuners are involved in several different communications applications including mobile phone communications and analog and digital TV reception. Tuners are often used to convert a portion of a received RF broadband signal into an IF output signal, which, for example, may later be digitized or processed to baseband. Generally, RF tuners are considered to be either “fixed frequency” or “agile.” Conventional fixed frequency tuners are generally able to utilize a relatively wide bandwidth portion of an incoming RF signal. For instance, known fixed frequency tuners are capable of utilizing approximately one percent of a received RF broadband signal. However, fixed frequency tuners are often undesirable in several applications because they effectively receive only a single, fixed frequency band. As such, fixed frequency tuners are unable to utilize frequency spectrum outside of a predetermined band.
Agile RF tuners are often desirable because they can be tuned to effectively receive virtually any input spectrum. However, conventional agile RF tuners are limited because they are able to process only a relatively small portion of an incoming RF signal. For instance, conventional agile RF tuners are capable of receiving an input between 50 MHz and 860 MHz; but, these tuners are only able to convert approximately 6 MHz to 8 MHz of that input spectrum to an IF output signal. As such, conventional agile RF tuners utilize approximately 0.6% to 1% of input bandwidth. This, of course, leaves much to be desired in several common applications.
In view of limitations associated with known RF tuners, a need exists for an agile RF tuner that is able to convert a wide portion of received RF signals into an IF signal. As will be discussed in greater detail, embodiments of the present invention satisfy such a need.